title: Phase separation induced by ladder-like polymer-polymer complexation.
abstract: Polymer-polymer complexation in solvent is studied using an extension of the self-consistent field theory. The model polymers are capable of forming ladder-like duplex structures. The duplex formation occurs with an abrupt change of entropy, resulting in a first-order transition. Moreover, the complexation can be stabilized by solvent-polymer interactions, instead of the usual specific binding interactions. Various types of unconventional phase diagrams are predicted. For example, phase separation with decreasing χ-parameter between duplex polymer and solvent can be induced, leading to a lower critical solution temperature (LCST) behavior. Multiphase coexistence points at which two, three, or four phases coexist are also obtained. Under certain conditions a homogeneous phase becomes unstable when the polymer chain length is decreased, in contrast to the standard Flory-Huggins theory.
authors.affiliation: Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, Canada. nakamur@caltech.edu
authors.forename: Issei
authors.initials: I
authors.lastname: Nakamura
authors.forename: An-Chang
authors.initials: AC
authors.lastname: Shi